High Efficiency Video Coding (HEVC) is a new video coding standard being developed jointly by ITU-T, also known as the Video Coding Experts Group (VCEG), and by ISO/IEC, also known as the Moving Picture Experts Group (MPEG) in the joint collaborative team on video coding (JCT-VC).
A video input signal has multiple frames. HEVC divides a frame into rectangular blocks or LCU (largest coding units) or macro-blocks of 16×16, 32×32 or 64×64. An optimal size of the LCU is selected based on the video content. The rectangular blocks can be predicted from previously decoded data either by motion compensated prediction or intra prediction. The resulting prediction error is coded by applying block transforms based on an integer approximation of the discrete cosine transform which is followed by the quantization and coding of the transform coefficients. In this coding scheme, discontinuities can occur in the reconstructed video signal at the block boundaries which are known as blocking artifacts. The blocking artifacts can, for instance, arise due to different intra predictions of the blocks, quantization effects and motion compensation. De-blocking filters are used in the video coding standards in order to combat blocking artifacts. De-blocking filtering is one of the most computation intensive blocks in HEVC and increases the video decoder/encoder complexity. Therefore, improved de-blocking filters are required to achieve bit rate reduction in HEVC